Some things never change…

Asteroids are rocky leftover pieces from the planetary formation era that never ended up becoming planets. They orbit our Sun out in the asteroid belt, but they are too small and weirdly shaped (thanks to impacts!) to be classified as planets. To give a sense of the size range of asteroids, the largest asteroid, Ceres, is 1000km in diameter, and most asteroids are much smaller than that. (Fun fact: Ceres’s mass is approximately the mass of every other asteroid combined.) Compared to Earth, which is 12,742 km in diameter, these asteroids are tiny!

Here are some famous asteroids, to give you a sense of what we’re talking about!! (Image credit: Wikipedia)

But why do we even care about these potato-looking space chunks? Asteroids help us understand how our solar system formed, because they have stayed the same since the beginning of our solar system. By examining the properties of asteroids, we can uncover details about our solar system’s formation and compositions. Only a select few asteroid masses are actually known (by using our favorite equation: Newton’s Version of Kepler’s 3rd Law!!), but those masses help scientists estimate other asteroid masses, calculate densities, and therefore use those densities to figure out the compositions!! Asteroids are made of rock and metal, since these materials could condense beyond the frost line.

One interesting thing is that we have studied meteorites (asteroids that have made their way to Earth), and we have observed several different categories of meteorites. There are meteorites that contain small bits of water and carbon-rich compounds, which are essential for life to exist. The fact that we have water and life on Earth can be explained by the fact that those asteroids, which formed beyond the frost line, brought us water and the compounds needed for life!!